1. Technical Field
The present invention relates to a power source circuit shut off device, and particularly relates to a power source circuit shut off device (a service plug) that shuts off a current by opening a power source circuit.
2. Background Art
In the past, a power source circuit shut off device (a service plug) is mounted on an electric vehicle and is built in a power source circuit which is adapted to supply power to a load from a battery and opens or closes the power source circuit on an as-needed basis. A capacity of a power source as a battery of an electric vehicle having, mounted thereon, the above kind of power source circuit shut off device, is markedly higher as compared to those of regular gasoline engine vehicles and the like. Therefore, in a case where the power source circuit shut off device is to be mounted on a vehicle, a current is shut off in a state that a power source circuit is opened (shut off) (see, e.g., JP-A-2000-322983).
FIG. 9 is a perspective view showing a plug constituting a related power source circuit shut off device. FIG. 10 is a perspective view showing a situation in which the plug constituting the power source circuit shut off device shown in FIG. 9 is going to be attached to a plug attachment section to which the plug is to be attached.
As shown in FIGS. 9 and 10, the above described power source circuit shut off device 110 includes the plug 101 having a terminal metal fitting 103, a housing 104 provided with an opening section 140E which is adapted to allow the terminal metal fitting 103 to be attached and a lever 105 to be rotatably attached to the housing 104, and the plug attachment section 102 having a second terminal metal fitting (not shown) to be connected to the terminal metal fitting 103 and a second housing 107 to which the second terminal metal fitting is to be attached. The housing 104 is brought into close proximity to the housing 107. In association with rotation of the lever 105, from a terminal contact position at which a tip portion of the second terminal metal fitting is first brought into contact with the terminal metal fitting 103 before the tip portion is accommodated in the second housing, the tip portion of the second terminal metal fitting is advanced into the innermost side of the terminal metal fitting 103, and then the housing 104 is accommodated in the second housing 107 and the housing 104 is position on a complete fitting position at which the opening section 140E is closed by the second housing 107. That is, in a state that the housing 104 is positioned at the terminal contact position, the terminal metal fitting 103 connected to the second terminal metal fitting is exposed from the opening section 140E provided on the housing 104. Meanwhile, a direction of arrow Z shown in FIGS. 9 and 10, indicates a direction that the housing 104 is brought into close proximity to the second housing 107.
The rotation of the lever 105 is restricted on the terminal contact position and in a half fitting state in which the housing 104 is positioned between the terminal contact position and the complete fitting position before the housing 104 is positioned at the complete fitting position from the terminal contact position with respect to the second housing 107. In a case where the lever 105 is rotated in a state that the housing 104 and the second housing 107 are positioned at the terminal contact position or in the half fitting state, the rotation of the lever 105 is restricted. Therefore, an operator may stop the operation of rotating the lever 105, further bring the housing 104 into close proximity to the second housing 107 so as to position the housing 104 on the complete fitting position, and then the operator needs to rotate the lever 105.
However, the above related power source circuit shut off device 110 has the following problems. That is, the housing 104 provided at the related power source circuit shut off device 110 has the opening section 140E which is adapted to allow the terminal metal fitting 103 to be attached. The terminal metal fitting 103 attached to the housing 104 is exposed from the opening section 140E at the terminal contact position at which the housing 104 is brought into close proximity to the second housing 107 so that the tip portion of the second terminal metal fitting is first brought into contact with the terminal metal fitting 103 before the housing 104 is accommodated in the second housing 107. Therefore, in a case where an operator mounts the power source circuit shut off device 110, the operator may erroneously contact the terminal metal fitting 103 connected to the second terminal metal fitting so as to possibly receive an electric shock.